UK Infrared Telescope
UK Infrared Telescope
(UKIRT) The British infrared telescope sited on Mauna Kea, Hawaii, at the very high altitude of 4200 meters. The site is well above the main weather layers and the bulk of atmospheric water vapor, opaque to most infrared wavelengths; in addition there is excellent seeing for work at visible wavelengths. The telescope is funded by the UK (by SERC), the Netherlands, and Canada, and is run by the Royal Observatory, Edinburgh. It became operational in 1979. The mirror is 3.8 meters (150 inches) in diameter, making the instrument the world's largest infrared telescope. It is unusually thin (29 cm) and weighs only 6.6 tonnes, allowing an extremely lightweight supporting structure to be used. The mirror surface has been ground sufficiently accurately that it can also be used at visible wavelengths for short exposures.A full range of cryogenic (very low temperature) facilities is provided for cooling the detectors in order to reduce spurious signals generated by the warmth of the detectors. There are also means for removing spurious signals generated by the telescope itself. The instruments mounted at UKIRT's Cassegrain focus include infrared spectrometers and photometers; the latter work at various wavebands – optical, infrared (1–5 μm, 4–35 μm), and submillimeter (0.3–1 mm). Heavier instruments are mounted at the coudé focus.